1. Field of the Invention
The present invention relates to a sheet feed scanner, and more particularly, to a paper pressing device for flattening the paper onto the scanning module.
2. Related Art
A general automatically sheet-feed mechanism for a multi-function peripheral (MFP) utilizes a paper track to move papers to the scanning module. To ensure the desirable quality of scanned images under the circumstance that papers are moved at a high speed, a pressing mechanism must be disposed in the MFP for pressing the papers such that they are flattened onto the surface of the transparent substrate for the scanning module, so as to achieve a stable scanning effect and desirable scanning quality.
As shown in FIG. 1, it is a schematic sectional view of a sheet feed scanner with a paper pressing device in the conventional art. The paper pressing device includes a pressing board 31 and a spring 32, wherein the pressing board 31 is pivotally connected to a pivot element 40 of the scanning device. Generally, the scanning device has a first body 10 and a second body 20, and a paper track 50 is formed therebetween for a paper to be scanned to pass through. The first body 10, an upper portion of the scanner, is provided with at least one pivot elements 40 having a pivot hole 41. The second body 20, a lower portion of the scanning device, is provided with a scanning module 21. A transparent substrate 22 is disposed above the scanning module 21, and made of transparent materials, such as glass and reinforced plastic. In the paper pressing device of a scanning device, by utilizing the elastic force provided by the spring 32, and cooperated with the pressing board 31, the spring 32 pushes the pressing board 31 to press it towards the transparent substrate 22, such that the paper to be scanned above the scanning module 21 is pressed, and being flattened onto the surface of the transparent substrate 22. Thus, a preferred optical effect is achieved when the scanning module 21 is used for scanning, so as to avoid the poor scanning quality caused by defocusing of the scanning module 21.
The shaft of the pressing board 31 is inserted into the pivot hole 41 of the pivot element 40, such that the pressing board 31 can only rotate with respect to the pivot element 40, that is, the pressing board 31 only has a moving margin with one degree of freedom. When the paper is scrolled to the scanning module 21 to be scanned, the pressing board 31 only presses the paper by way of pivotally rotating, such that the pressing effect cannot be achieved on the whole surface. As a result, the paper is partially flattened onto the surface of the transparent substrate 22; therefore, the recognition quality of the scanning module 21 is significantly reduced.